x86/microcode: Get rid of the schedule work indirection

mainline inclusion
from mainline-v6.7-rc1
commit 2e1997335ceb6fc819862804f51d4fe83593c138
category: feature
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I8XRMW


CVE: NA

--------------------------------

Scheduling work on all CPUs to collect the microcode information is just
another extra step for no value. Let the CPU hotplug callback registration
do it.

Intel-SIG: commit 2e1997335ceb x86/microcode: Get rid of the schedule work indirection.
Microcode restructuring backport.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231017211723.354748138@linutronix.de


[ Aubrey Li: amend commit log ]
Signed-off-by: Aubrey Li <aubrey.li@linux.intel.com>